The metabolism of glycogen in human skin fibroblasts grown in tissue culture will be studied from the point of view of understanding the enzymatic basis for the prolongation of glycogen half-life and the intralysosomal "storage" of glycogen which occurs when such cells are exposed to the non-metabolizable disaccharide, trehalose, during and after their growth to confluence. Normal cell lines and also cell lines grown from the skin of patients with various "glycogen storage diseases" will be used. Of particular interest will be the comparative study of cell lines derived from children with the fatal, "infantile" form of Type II glycogen storage disease, and also cell lines from older patients who have the nonfatal, "adult" variant of this disease. The general purpose of this research is to assess the quantitative significance of the "lysosomal pathway" of glycogen catabolism in normal fibroblasts and in fibroblasts from patients with various types of glycogen storage disease. BIBLIOGRAPHIC REFERENCES: The Lysosomal Alpha-Glucosidase of Human Fibroblasts. Louise M. Waindle, Barbara I Brown and David H. Brown. Federation Proceedings, 35, 1727 (1976). (Abstract No. 1880). Analytical Problems In The Detection of Inborn Errors of Carbohydrate Metabolism Using Human Tissues, Blood Cells, and Cultured Fibroblasts. David H. Brown. Plenary Lecture. Proceedings of the European Meeting for Biochemical and Instrumental Analysis and of the International Congress, "Analytica 76", Munich, April, 1976 (in press).